So I adopted 4 tiger barbs and when I got them they where very stressed and dark but they soon got their color and became happy. But yesterday I I got the brine shrimp and I don't know if that has anything to do with this but when I got up this morning and turned their light on 3 of them where very pale like a silver/whitish color and they just stayed in a little group together not moving around just swimming in place. But after I fed the other fish and got ready they where up and moving around and had color to them. Is something going on or do they just do that?